• 한국자기학회지
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• 제9권6호
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• pp.271-277
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• 1999

M ssbauer 분광법을 이용하여 비정질합금 Fe83B9Nb7Cu1의 자기적 성질을 연구하였다. 개선된 Vincze의 방법을 적용하여 각 온도에서 초미세자기장, 이성질체 이동치, 그리고 quadrupole line broadening의 분포함수들을 얻었고 큐리온도는 393K, Hhf(0)는 231kOe로 산출되었다. 환산된 평균 초미세 자기장(reduced average hyperfine field)의 온도 변화는 S=1 자기화 곡선에 비해 급히 감소하는 양상을 보였고 이를 설명하기 위해 Handrich의 분자장 이론에서 교환 상호 작용의 척도인 에 =0.75-0.64(T/Tc)+0.47(T/Tc)2의 온도 의존성을 도입하였다. 평균 초미세 자기장(Hhf(T))은 저온에서 스핀파 여기에 의한 공식 Hhf(T)=Hhf(0)[1-0.44(T/Tc)3/2-0.28(T/Tc)5/2- ]으로 분석하였고, 큐리온도 부근에서는 1.00[1-T/Tc]0.39의 관계를 갖는 것으로 나타났다. 초미세 자기장 분포곡선의 선폭은 13K에서 102kOe (3.29 mm/s)였으며, 오도가 증가함에 따라 감소했다. 큐리온도 이상에서 평균 quadrupole splitting값은 0.43 mm/s였으며 quadrupole 이동치 분포에 의한 선폭 증가는 13K에서 0.1 mm/s, 320K에서는 0.072 mm/s 정도로 초미세 자기장 분포나 quadrupole line broadening에 의한 선폭 증가보다 작았다. 이성질체 이동치의 온도 변화에 Debye 모형을 적용하여 Debye 온도를 D=424K로 산출하였다.

• 전자통신동향분석
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• 제36권5호
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• pp.92-102
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• 2021

Owing to various restrictions in-field application, the low-speed, low-power-based industrial Internet-of-Things (IoT) network built in extremely harsh industrial environment sites requires multi-hop, channel hopping, and low-latency transmission characteristics. In the past, wired networks were used in industrial facilities; however, network technologies based on the Industrial IoT Network standard standardized for industrial applications, such as WirelessIO link, WirelessHART, SmartMesh, and eStar Link satisfy industrial requirements. Recently, the use of industrial IoT networks in industrial facilities has rapidly expanded. This paper covers the developments in industrial IoT network technologies and summarizes the major industrial IoT standard technologies that meets the requirements of industrial sites.

• E2M - 전기 전자와 첨단 소재
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• 제9권4호
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• pp.404-409
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• 1996

The structural and electric properties of $Y_{1-x}$YbF$_{x}$Ba$_{2}$Cu$_{3}$O$_{7-y}$(x=0.0, 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6) have been investigated by using XRD(X-ray diffraction), TMA(thennomechanical analysis), NMR(nuclear magnetic resonance) analysis and four probe method. $Y_{1-x}$YbF$_{x}$Ba$_{2}$Cu$_{3}$O$_{7-y}$ samples were prepared by conventional solid-state reaction method using $Y_{2}$O$_{3}$, BaCO$_{3}$, CuO and YbF$_{3}$ power. TMA and high temperature XRD results shows that orthorhombic to tetragonal phase transition occurs in the unfluorinated 1-2-3 sample while the phase change is not observed in the fluorinated 1-2-3 samples. Superconducting transition temperature(T$_{c}$) increases with increasing YbF$_{3}$ content ; T$_{c}$, of the sample reaching maximum of 102K for x=0.3, and then decreases with further increasing YbF$_{3}$ content. The structural analysis and T$_{c}$ results shows that the fluorine doping stabilize the orthorhombic phase, together with the increase in T$_{c}$.}$ c/.TEX> c/.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1993년도 가을 학술발표회 논문집
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• pp.97-102
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• 1993

In the country, due to short comings of natural aggregates of good quality, it is common to use crushed stones. However, the investigation has not been done on the chemical reaction of crushed stones. This study tested and analyzed the aggregate chemical reaction by Petrographic Examination(ASTM C 295),Chemical Metho(ASTM C 289) and Mortar-Bar Method (ASTM C 227). As a result, most of test aggregates didn't show any reaction but many have common deleterious mineral. Therefore, there exists the possibility of chemical reaction in petrographic point of view.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 추계학술대회 논문집
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• pp.101-102
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• 2007

• Journal of Welding and Joining
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• 제32권3호
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• pp.102-107
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• 2014

Boiler equipment in power plant is always being operated in harsh conditions and severely exposed to the extreme environment of high temperature. Therefore periodically the state of devices should be checked, diagnosed, and analyzed to ensure the reliability of the equipment. Traditionally, such a diagnosis is based one or two physical properties of the sample taken from the equipment like hardness, microstructure, etc.. However, to enhance the confidence of the diagnosis, it is necessary to synthesize those properties together. This paper is to propose such a synthetic procedure for SA213-T12(1Cr-0.5Mo) which was developed to be used in $565^{\circ}C$ below condition. Creep test and accelerated degradation test were performed simultaneously, and the physical properties such as microstructure, tensile strength, yield strength, hardness, and indentation properties were measured. This paper proposes a method of determining the remaining life by quantitative comparison. It will provide the basis of evaluating life assessment more objective and reliable.

• 한국결정학회지
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• 제5권1호
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• pp.1-6
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• 1994

화합물 VP6N3018C243H60의 두 가지 가능한 공간군은 PT,a=14.O22(1), b=12.644(2), c=12.640(1)A, a=80.38(1), β=102.12(1), y =102.16(1), V=2124.1A3, Z=2, u=0.47cm-1,d==1.46g/cm3, Fo>4c IfoI인 3350윤의 독립반사강도에 대하여 R=0.083 과 C2/c, a=19.32(2), b=16.32(2), c=14.02(1)A, β= 105.98(5), V=4348.2A3, Z=4, Fo>4o IFoI인 1590개의 독립반사강도에 대하여 R=0.083 이다. 주간군 Pi의 경우 단위포내에 두 분자가 있는데 각 분자내의 바나둠 원자가 특수치치에 있어 중심대칭에 의하여 한 분자를 이루고 있으므로 단위포내의 비대칭단위는 두개의 bis(timetalhosphate)vanadate 반분자와 3개의 tetraethylammDnium분자로 되어있다. 공문군 C2/c의 경우 bis(trimetaphosphate)vanadate 한분자의 vanadium 원자가 중심대1칭을 갖는 변광단동치에 있으며, 3개의 tetrethylammonium 분자중 한 분자내의 CL2, N2, C25 원자들을 2-회회전대칭축이 지나므로 bis(trimetaphosphate)vanadate 반분자와 tetraethylammonium 3/2 분자가 비대칭단위를 이루고 있다. 두 경우 공히 vanadium원자를 배위하고 있는 6개의 산소원자가 8함체를 이루며 nitrogen원자와 결합하고 있는 4개의 carbon 원자들은 모두 disorder되어 있어 nitrogen원자의 주권에 있는 8개의 carbon 원자들은 불규칙한 12면체를 이루고 있다.

• 한국표면공학회지
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• 제26권1호
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• pp.23-30
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• 1993

Iron component in wasted hydrochloric etching solutions from steel works were recovered by electrolysis. The electric conductances of the solutions, as the function of the bath temperature and the ferrousion concen-tration, were measured and the result of the original solution was K=(0.0012+0.0005$\times$10-3T-0.1160$\times$10-6T2)$\times$102S.m-1(T in $^{\circ}C$) The current efficiency was better for the bath using a soluble steel plate anode than for the bath using an insoluble platinized titanium one. Densed electrolytic iron having the purity of higher than 99.99% was ob-tained at the electrolysis conditions of the cathodic current density of 15A/dm2, the bath temperature of $70\pm$$5^{\circ}C$ and the ferrous ion concentration of about 100g/l. The morphologies of the deposited iron were observed by SEM.

• 자연과학논문집
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• 제4권
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• pp.95-102
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• 1991

규산삼석회$(C_3S)$의 수화반응에 있어서 $T1_2CO_3$의 농도변화에 따른 영향에 대해서 Isothermal microcalorimeter 등을 이용하여 조사한 결과, $T1_2CO_3$의 존재로 인하여 $C_3S$의 수화반응은 촉진되고 $C_3S$의 농도가 급격히 감소된다. 또 $T1_2CO_3$의 농도증가로 인해서 수화반응속도도 증가하고 있다. $T1_2CO_3$ 첨가에서 수화된 $C_3S$의 분석결과로는 반응초기에 $CaCO_3$가 나타나고 있으며, $T1_2CO_3$의 촉진작용이 수화반응의 초기에 있어서만 더욱 분명하게 나타나고 있음을 $C_3S$의 비휘발성 수분함량과 수화도로서 알수 있고 $C_3S$ paste와 접촉하고 있는 액상의 조성은 $T1_2CO_3$의 존재로 인하여 $Ca^(++)$이온과 $OH^-$ 이온의 농도가 상당히 변화하고 있음을 알 수 있다.

• 대한소아치과학회지
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• 제8권1호
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• pp.89-102
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• 1981

1147 preschool children aged from 3 to 6 living in some farm villages in Kyungki-do were surveyed on dmf and distribution of dental caries in primary dentition. The results were as follows: 1. dmf rate ... 92.76 % boy ... 94.52 % girl ... 90.5.5 % 2. dmf t rate ... 37.07 % dmf t index ... 7.09 3. dmf s rate ... 13.74 % dmf s index ... 13.14 % 4. df t index ... 6.94 5. Each percentage of d, m & f per dmf teeth d rate ... 89.96 % m rate ... 7.24 % f rate ... 2.67 % 6. Most frequent site of dental caries in each tooth $\underline{A}$ mesial $\overline{A}$ distal $\underline{B}$ mesial $\overline{B}$ distal $\underline{C}$ distal $\overline{C}$ distal $\underline{D}$ disto-occlusal $\overline{D}$ disto-occlusal $\underline{E}$ linguo-occlusal $\overline{E}$ occlusal 7. Order of caries susceptibility $\overline{E}$ $\underline{E}$ $\overline{D}$ $\underline{D}$ $\underline{A}$ $\underline{B}$ $\overline{C}$ $\underline{C}$ $\overline{B}$ $\overline{A}$ 8. All the values in caries criteria showed a marked increae from those of 1968.